Phthalates in school supplies

4. To what extent are people exposed to phthalates?

The diet, particularly fatty food, is responsible for most
of the DEHP exposure in adults. Source: Steve Woods

The EU-Risk Assessment
Reports (RAR) on various
phthalates have made a
detailed assessment of exposure based on known
concentrations in food, the
environment and materials, and models that predict what
proportion of the substance is taken up by the body. For
DNOP, however, no such
assessment report is available and information on use patterns,
occurrence, and human exposures is lacking.

More recent studies assess human exposures to
phthalates by measuring the
biological breakdown products in urine, since this method gives
more precise estimates. One such study on children in Germany
showed that exposure was higher in boys than in girls, and
children aged 6-7 years were significantly more exposed than
children in the age group 13-14 years.

Overall, our knowledge of how the body takes in
phthalates and how it
transforms, metabolises and
eliminates them is limited. In addition, the extent to which age
influences these processes has not been sufficiently evaluated.
Still, the average exposure of children is known to be
approximately twice that of adults. Different lifestyle factors,
eating behaviours, and the ingestion of dust from indoor
surfaces may also play a role. A recent study from Germany
comparing concentrations in
the food and in the urine of 5-8 year old boys indicated that
diet was responsible for about 50 % of their exposure to
DEHP, so other important
sources must exist. For adults, DEHP exposure is mainly due to
diet, particularly fatty foods.

While DEHP was the
phthalate most commonly used in consumer products in the 1990s,
it has since been increasingly replaced by
DIDP because of health
concerns. Between 1999 and 2004, the proportion of DEHP in total
phthalates use decreased
from 42% to 22% and the proportions of
DINP and DIDP increased
from 35% to 58%. The change in use has been reflected in a
change in exposure to these two phthalates. A study in Germany
on 20-29 year olds showed continuous decrease in DEHP exposure
from 1996 until 2003 and a corresponding increase in DINP
exposure.

A US study calculated the daily intake of
DINP in children of
different ages, based on estimates of how long children put
products containing DINP into their mouth and of how much would
pass into the body. The average estimate was 0.0057 mg/child/day
for children aged between 3 and 12 months, but there were very
large variations, with 5% of children expected to take in 0.0943
mg/child/day or more. The values for children at 13-26 months
were considerably lower with a mean of less than 0.001
mg/child/per day. At present, there is a lack of direct
measurements of the breakdown products of DINP or other
phthalates in the urine of
children that would allow a more precise assessment of exposure.

In conclusion, the exposure data based on urine samples
indicate that average exposures are well below the tolerable
daily intake (TDI) for
DEHP, but it may approach
or even exceed the TDI in some highly-exposed groups of
population, notably people exposed through medical procedures
such as kidney dialysis.
For the other phthalates
studied, calculated exposures are below the TDIs except for
DBP. A significant portion
of the population may be exposed to doses of DBP above the TDI
and efforts to further reduce exposures are needed.
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